He is known for his provocative stunts, which have included tattooing the backs of drug addicts, and spraying a group of stateless Iraqis with foam. But the Spanish artist Santiago Sierra provoked outrage among Jewish groups in Germany yesterday with his latest work - a homemade gas chamber set up in a former synagogue.

The Mexico-based artist has parked six cars outside the synagogue and attached their exhaust pipes to the building using plastic tubes. It is then filled with deadly gas. Visitors are invited to go inside one by one wearing a gas mask, escorted by a firefighter. Before being allowed in, they have to sign a disclaimer stating they realise the room is full of carbon monoxide.

The project opened to the public on Sunday, creating huge queues, and runs until the end of April.

Sierra says the installation - entitled 245 cubic metres - is a protest against the "banalisation of the Holocaust".

Sierra's previous artistic targets have included capitalism, exploitation and the labour market. Yesterday, however, Jewish leaders in Germany reacted furiously. They described the installation in the small Rhineland town of Pulheim as "an abuse of artistic freedom".

"It's a scandal. It's an unbelievable provocation at the expense of Holocaust victims," said Stephan Kramer, secretary of Germany's central Jewish council. He added: "It doesn't just insult them but the entire Jewish community."

Others were also left seething. "It's despicable," Ralph Giordano, a writer and Holocaust survivor told German radio. "What's artistic about attaching the poisonous exhaust from six cars into a former synagogue?" He added: "And who gave permission for this?"

Local mayor Karl August Morisse yesterday refused to comment. Earlier, however, he defended his decision to stage Sierra's work in the synagogue, which is used as a cultural centre, and has previously hosted other international artists. The synagogue, on the outskirts of Cologne, survived the second world war, and is next to a restored Jewish cemetery desecrated by the Nazis.